Growers are increasingly adopting latest herbicide strategies in canola for improved weed control longer into seasons and cleaner paddocks in following years, as well as to reduce pressure on traditional chemistries.
Following its registration for post-emergent application in canola to target grass and broadleaf weeds, in addition to its pre-emergent application, Tenet has been strongly used by growers, particularly in Roundup Ready and triazine-tolerant (TT) cropping systems.
Tenet contains the active ingredient, metazachlor, and is the only Group 15 herbicide that can be applied post-emergent or incorporated by sowing (IBS) in conventional and herbicide-tolerant canola. It provides residual control or suppression of key grass and some broadleaf weeds, including annual ryegrass, barley grass, brome grass and capeweed.
Kim Gooding, manager and agronomist at Kukerin Rural Services in WA, says Tenet, developed by Adama Australia, was especially being used with Roundup Ready canola crops that were helping to tidy-up grassy paddocks.
“Tenet is keeping the weeds at bay, and it is helping the glyphosate to work much better by targeting smaller weeds at the time of the second application. It is taking the pressure off the second glyphosate spray,” Kim says.
“In a lot of cases, after using Tenet with the first glyphosate spray, you’re looking at the paddock thinking it almost doesn’t need the second application, but you do it anyway because you know they'll be there.
“It has become a really good option to preserve the life of glyphosate and maximise its effectiveness on smaller weeds, rather than trying to hit bigger weeds at the label rates in Roundup Ready systems.
“If you’re not using Tenet in those paddocks, which are high pressure, you’re putting much more pressure on the glyphosate.”
He says the post-emergent applications were achieving extended residual control deeper into seasons.
“If you’re also getting shading of weeds and you can’t hit them with glyphosate in those second or third applications, you’d like to think the Tenet is reducing those numbers.”
“By doing this, we’re definitely noticing cleaner crops the next year because we’re able to hit more weeds consistently with the second and third glyphosate applications while the Tenetis working in the background for us, picking up those weeds that are hiding underneath when you have a bigger canopy.
“Particularly with new farms, where they’ve probably been let go a little, we’ve been smashing it with this system to try and help the future rotations,” Kim says.
Adama Australia’s South Australian market development manager André Sabeeney confirms with clethodim activity starting to fail in areas, Tenet is proving to be an excellent residual option in mixes with post-emergent herbicides.
“We have seen a dramatic increase in ryegrass control in some trials, especially where clethodim is losing its edge. Growers and agronomists are often trying to balance spraying when weeds are small, but allowing enough time to ensure the population has emerged and then using Tenet as a mix partner at an early spray timing helps reduce these escapes due to its residual activity,” André says.
“It’s taken up mostly through the roots and you can mix it with pretty much anything post-emergent in canola. In fact, it is strongly recommended to be applied in mixes with glyphosate, Liberty, clethodim and imidazolinone herbicides. And add oils too – it doesn’t increase crop damage from other herbicides in the mix.”
He says in southern areas, many growers wanted to use Tenet post-emergent because other options were limited and they wanted to avoid damaging crops, whilst they also were using different mode of action herbicides pre-emergent.
“The effective use of robust pre-emergent herbicides in canola has become standard practice and most growers are doing this well, but many of these herbicides are incorporated by sowing (IBS), which removes the herbicide-treated soil out of the furrow to increase crop safety. is system often allows early ryegrass germination in ‘untreated’ furrows and that’s where Tenet has a perfect fit.
“Applied at this early stage in a mix with clethodim – and glyphosate in glyphosate-tolerant crops – allows improved control and some residual activity on weeds yet to germinate, “André says.
Adama Australia’s Western Australian market development manager Bevan Addison, says with the ongoing concern over future paraquat herbicide applications, achieving good grass control and safeguarding glyphosate effectiveness was becoming even more important for growers.
Bevan says herbicide applications with Tenet in canola had continued to show encouraging results and demand for the product had escalated as growers increasingly recognised its value in their programs.
